1. Field of the Invention
The present invention relates to a sliding caliper disc brake and more specifically to a guide means for slidably mounting the caliper member on the carrier member of the disc brake assembly.
2. Prior Art
The problem with known guide means is the difficulty of locating the caliper member adequately against spurious movements under heavy vibration and braking while at the same time ensuring that the caliper member can slide freely relative to the carrier member.
It has been proposed in the past to mount the caliper member on the carrier member by means of a pair of pins which are slidable in respective openings in one of the members and are secured to the other of the members. However, in such constructions, it is necessary to center the pins very accurately in their openings to avoid binding in operation resulting in differential braking at different vehicle wheels arising from different proportions of the available hydraulic line pressure needed to overcome the initial resistance to sliding. Furthermore, under heavy braking, the carrier member may deflect to produce intermittent binding of the pins in their openings resulting in stress to the pins and parts of the caliper member.
In an attempt to solve this problem in the past, the pins have been encased within rubber bushings. While this reduces the likelyhood of binding there is a tendency for brakes to heat up which may cause deterioration of the rubber. In the U.S. Pat. to Unterberg No. 4,093,044 granted June 6, 1978, the guide means for the caliper includes a pair of pins disposed with a snug sliding fit in a pair of openings in the carrier member. The caliper is connected to the pin by means of a resilient element adapted to flex so as to absorb the loads produced by distortion of the carrier member and thereby resist binding of the pins in the opening.